State of Charge (SoC) Meter
User Guide
PLEASE READ ENTIRE GUIDE BEFORE INSTALLATION OR ANY POWER-UP ATTEMPT
Lithionics Battery LLC
User Note: The State-of-Charge Meters are produced in two series of voltage ranges as follows:
Model 4S-8S: Must be used on 12 to 24 volt battery systems only (max 30.0V)
Model 9S-16S: Must be used on 28 to 48 volt battery systems only (max 60.0V)
Model 17S-96S: Must be used on 54.5 to 307 volt battery systems only
Description:
The Lithionics Battery SoC meter is designed to track battery state of charge (percent of usable
energy left in the battery) as well as other useful data variables. Tracking state of charge is
accomplished by an internal, high sensitivity hall-effect sensor. SoC meter data will only be
correct if the configuration variables are set correctly, which are pre-set initially by Lithionics
Battery. If they are ever accidently modified a record of the default values is included in this
manual for your reference. It will also track and display live amperage (A), live wattage (W),
battery voltage (V Pk), temperature (F/C), amp hours (Ah), watt hours (Wh), etc. The meter will be
most accurate if the battery is fully charged on a regular basis. If the battery is always partially
charged then the SoC meter reading may drift long term and will become less accurate. When the
most accurate measurements are required it is recommended to do a full charge weekly.
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Description (continued):
The Lithionics Battery SoC Meter system is comprised of the main SoC sending box for collecting and
computing data points. List of accessories for the SoC Sending Box:
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Rectangular SoC Display
Round SoC Display Gauge Pod
USB output
Serial DB-9 output
TTL output, Analog (0-5V) outputs
Generator Control Module
Bluetooth connectivity
3-Bit Register
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Initial Installation Instructions
Upon unpacking please inspect all components for obvious damage due to shipping.
The SoC Sending Box has BATTERY +, LOAD +, and a SoC NEGATIVE REFERENCE WIRE which must be
connected correctly for accurate SoC calculation. Please refer to the chart and instructions below.
1. Begin by turning off ALL LOAD devices both charging and discharging. Turn the battery off, or
if it is equipped with an external NeverDie unit, turn it off as well.
2. Connect the SoC NEGATIVE REFERENCE WIRE to the battery negative (-) terminal.
3. Connect the battery positive + to the BATTERY + on the SoC Sender Box.
NOTE: If you have an external NeverDie unit on your battery system the Load + of the
NeverDie must be connected to the Battery + on the SoC Sender Box.
4. Connect the LOAD + to your charge and discharge loads (ideally a common bus bar).
5. Connect any accessories you may have ordered with your SoC Meter system.
6. Power the battery or NeverDie unit back on.
7. Installation complete.
Weather Resistant Display Port Connection:
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When connecting the SoC Display via the weather resistant port on the front of the sender unit it is
especially important to pay special attention to the screw down connector.
1. Locate the two indentations highlighted in green below.
2. Connect the screw connector to the panel interface with the two highlighted indentations
mating with each other.
3. While pressing the ring down lightly, rotate the ring counter-clockwise until you feel a light
click. This aligns the ring threading with the panels mating threads.
4. Now turn the ring clock-wise to begin screwing the ring down. Keep note of any excess
friction which may indicate it is being cross-threaded. If this occurs stop immediately, unscrew the ring and start over. Inspect the ring to be “square” compared to the panel.
Using The SoC Meter’s Interface via SoC Display Unit:
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T h e SoC meter has a dual line LCD screen capable of showing 2 pieces of data independently.
Pressing the upper button scrolls through available data on upper line, pressing lower button
scr o lls t h r o u gh available data on the lower line. Any combination of data is possible on
t h e s e 2 lines. The following list explains all available data counters:
E █ █ █ █ █ █ F – Graphical representation of the Fuel Gauge. Each of the 6 bars corresponds to
approximately 17% of capacity.
100% Fuel – Percentage of digital Fuel gauge. Fuel is derived from SoC minus the Low Fuel setting
explained in the Calibration/Settings section below.
100% SoC – State of Charge. The percent of usable energy left in the battery.
23.4 A – Amperage. Instant current reading. A “+” sign in front of the value indicates charging
current. No sign indicates discharging current.
20000 W – Instant Wattage reading. This power value is derived by multiplying current and
voltage. This is useful to estimate how much instant power is passing through the battery
circuit. This value can be manually converted to horse power by the formula: Watts/745.7=HP
39.6 V Pk – Pack voltage reading.
82F Tmp – Instant temperature reading at the sender board location. Can be set to C or F. See
“Zero-Point Calibrations and Settings” section.
100.0 Ah – Remaining Amp Hour capacity of the battery.
3960 Wh – Remaining Watt Hour capacity of the battery. Watt Hour value is derived by
multiplying t h e Amp Hour value and the Pack Voltage together. This value will be changing
dynamically as voltage fluctuates with load.
Programming Menu via SoC Display Unit:
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The SoC meter’s Programming Menu is where you can enter constant settings. Although the
defaults are pre-loaded at the factory, you will need to access this menu to make minor changes
or if you are using the SoC meter on a different battery. It is also useful for fine tuning for your
application. It is very important these are entered accurately or SoC calculation will be inaccurate.
To enter the Programming Menu, locate the 2 SoC Meter Display input buttons.
Press and hold both buttons simultaneously for 6 seconds.
The SoC Meter will enter the Programming Menu.
-Press the upper button to scroll through the range of values.
-Press lower button to lock the value and move to the next screen.
NOTE: If no button(s) are pressed within 20 seconds then Setup Mode will time-out and
switch to display mode automatically.
Below is the listing of all setup screens and their variable descriptions. The factory default values
are recorded for you at the end of this document for your reference.
V Range – Voltage Range. Set this to your maximum voltage range. There are 2 ranges
available, “to 64V” and “to 340V”. For example, if your battery reaches max voltage of 43.2V
at the end of charge, then use “to 64V” range setting.
PackSize - Battery pack capacity. Settings are from 1Ah to 3000Ah. 0-50Ah are in 1 Ah
increments. 50Ah-3000Ah are in 10Ah increments.
Full Vlt – Full Voltage. Set this to the maximum voltage your battery reaches at the end of
charge. This will be used to sync the meter’s 100% SoC reading when the battery reaches this
preset level. You can calculate your maximum voltage by the following table:
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Min SOC – Minimal State Of Charge. This percentage value sets the “Empty Fuel Tank” level,
so the driver can go by a Fuel Gauge reading and not completely deplete the battery, to
preserve its lifecycles. For example, if this value is set to 20%, then Fuel Gauge will report 0%
when SoC is still at 20%. If you desire to use your battery to its full capacity and/or want the
Fuel Gauge to reflect true SoC, then set this value to zero.
CurrDir – Current Direction. Hall-effect sensor reports direction of DC current passing through
the sensor. It’s important for correct So C me te r functionality that the current is sensed in the
correct direction for charge/discharge. If this is set opposite you will see the gauge reporting
charging when you’re discharging and vice versa. In this case please reverse the setting. Current
should be reporting with a “+” sign during charge and without any sign during discharge.
TempComp – Temperature Compensation. At low temperatures batteries cannot supply
their entire capacity due to slowdown of electrochemical processes. This percentage value
reduces Fuel Gauge reading based on temperature drop, linearly from 25C to 0C and below,
such that Fuel Gauge reduction is equal to this value at 0C ( freezing point ). For example, if you
set this to 10% (the recommended value for Lithionics Battery cells), then the Fuel Gauge will
report 10% less capacity at 0C, linearly changing across a wide temp range. This value only
effects Fuel Gauge reading, SOC reading still remains true to battery capacity regardless of the
temperature.
Low Fuel – Low Fuel level. This percentage value determines the minimal Fuel Gauge level at
which the “Low Fuel” circuit is triggered. This is used for external signaling, such as OEM dash
boards, generator/charger relay, etc. On most setups this is not used and should be skipped.
TempUnit – Temperature Units. Set this to Fahrenheit (F) or Celsius (C).
ChargeEff – Charging Efficiency. This percentage value slows down rate of SoC climb during
the charge to compensate for battery losses during discharge. Recommended setting is 96%.
This would be much less for Lead Acid batteries, depending on their Peukert value and battery
application. For example, in electrics vehicles with high discharge rates, Peukert effect
is more pronounced, so this value must be set lower to more accurately report SoC and
Fuel Gauge values during partial charges. This setting must be tuned experimentally for best
accuracy. Ideal setting will cause SoC to reach 100% at approximately the same time as charger
is finishing up the full charge.
NOTE: This feature assumes that Pack Size is set to actual useful capacity of the battery at high
C rates, which is almost true for LiFePO4 cells, but not for Lead Acid batteries. Lead Acid battery
will have smaller useful capacity than its rated capacity, so Pack Size should be set to useful
capacity, so the SoC meter can reflect meaningful Fuel Gauge.
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DeadZone – Dead Zone. In some cases when temperature fluctuations are wide and fast, SoC
meter might show non-zero current reading when not expected. This is due to imperfect
temperature stability of hall-effect sensors. The SoC meter software compensates for this, but
in some extreme situations it may fluctuate resulting in small current reading when not expected.
Dead Zone allows ignoring small current readings when they are likely false (when small
reading starts after zero reading). During charging, when current is dropping during CV phase
the SoC meter will count it even in the Dead Zone. If small reading persists for over 60
minutes, it will be considered as false reading and thus ignored. You can turn off this feature
by setting this value to zero. Default 0.3A is recommended for best zero reading stability.
TestMode – Test Mode is designed for verification of external circuits at the factory. This can
be useful for testing outputs trigger settings as it will slowly cycle SOC% down and
back up repeatedly.
Out Mode – Controls the function of the optional output terminals. Default mode
= 0 and is common for most setups. Mode 1 turns the optional output terminals
into a 3 bit register. The 3 bit register signals SOC level in 8 bin ary values between
000 and 111.
SensType – Sensor Type. This is the hall-effect sensor type which is installed and set at the
factory. Options are 1000A or 2000A. Refer to the default values at the beginning of this user
guide.
CurScale – Current Scale. This function is used to modify the amps counted by the internal halleffect sensor. It is useful if you notice that the SoC reading is too high or too low. It can be
adjusted +/- 5.00%
IdleLoad – Idle Load (mA). This setting represents the constant idle load current powering the
SoC Meter and BMS system. This can be measured with a digital multi-meter in DC amperage
mode in series with the SoC NEGATIVE REFERENCE WIRE. Allowed range is 0mA – 200mA.
Calib..? – Calibrate Zero Point
This function performs a “zero-point” calibration. This is called a “zero-point” calibration because
the current flowing in or out is at zero state. Before performing this operation, you must ensure
that the battery is disconnected from any loads both charging and discharging so current is not
flowing in or out of the battery. Failure to do so will cause the SOC meter to have an inaccurate
zero-point calibration!
Setting this to Yes will perform the zero-point calibration when the enter button is pressed. It
takes a few seconds to determine the zero-point current levels so that the current sensor can
properly distinguish current direction and value. It’s critical that there is no current flowing in or
out of the battery at this point. It’s recommended to disconnect any loads both charging and
discharging from the battery before entering zero-point calibration. There is no input on this
screen, once the zero-point calibration is complete the meter will automatically return to normal
user mode.
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Input/Output Accessories
Optional Analog and Digital Outputs
NOTE: Outputs #1-3 are CMOS level 0-5V with 5mA limit.
#1 Low Fuel - The Low Fuel output circuit is 0V when inactive and 5V when active. It
corresponds to the Low Fuel setting in the user menu.
#2 Full Charge – The Full Charge output circuit is 0V when inactive and 5V when active. It
corresponds exclusively to 100% SOC condition.
#3 SOC 0-5V Analog – The SOC 0-5V Analog circuit represents 0%-100% SOC state. It will
linearly increase/decrease voltage according to SOC% state.
#4 5V 100mA max – A 5V reference voltage, 100mA max.
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Optional 3 Bit Register Output:
4 wires represent a 3 bit register. Outputs #1-3 represent a 3 bit register with binary output for
SOC %.
Outputs #1-3 goes 0-5V binary 0 or 1. Out3 is least significant bit (LSB). Out 1 is most significant
bit (MSB).
SOC =100%, all 3 bits are high
SOC=0% all 3 bits low
SOC <100% and >0% 3 bits represent binary values 0-7, each step corresponding to approx. 15%
SOC increment.
Optional Serial Data Output
Serial data output is supported over either a USB, TTL or DB-9 RS232 interface.
The USB interface emulates a virtual COM port. ASCII serial stream data is broadcast via USB or
Serial DB9. Any terminal program that can view/record serial data via a COM port is compatible.
At Lithionics we use the program “Putty.exe” to log and display data in real time (available at
putty.org). This fixed length data line is updated once every second. The file is saved real time,
viewable as plain text in a .log file. This data can be integrated into other applications that can
read data via a COM port.
COM Port Settings:
Speed/Baud
Data bits
Stop bits
Parity
9600
8
1
None
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Optional Bluetooth Module Connectivity
The Bluetooth module will output the same fixed length data stream as the serial data output
above.
Optional Generator Control Module Interface (AKA Fischer Panda Controller)
The Generator Control Module Interface is designed to work with generators that accept a closed
circuit start/open circuit stop signal such as in Fischer Panda generators. This module will
automatically start and stop the generator, as well as require a confirmation signal from the
generator that it is running. If the generator is not running once signaled to start, the alarm circuit
will trigger alerting you to a generator fault. In addition to this a momentary button can be short
pressed by the user to reverse the generators state at any time. This allows
convenience/opportunity charging along with automatic charging start/stop functionality.
The start and stop points of the generator can be user programmed as follows:
Low Fuel – When the SoC Meter is at the low fuel level (see page 5 Low Fuel) it will trigger the
generator to start automatically.
Full Voltage – When SOC full voltage is reached (see page 5 Full Vlt) the SOC meter calibrates to
100% and the generator is commanded to turn off.
There are 3 pairs of wires that need to be connected for the Generator Control Module to
interface correctly with the generator. They are:
Alarm – 2 wire isolated 2 amp 250V max N/O circuit (closes when active, opens when inactive).
Start – 2 wire isolated 2 amp 250V max N/O circuit (closes to start generator, opens to stop)
Run – 2 wire isolated input circuit. A 12V-24V max signal is expected from generator when the
generator has started. There can be up to a 2 minute delay between start signal and return run
signal, if not the Alarm circuit will activate. Alarm signal is reset when Run signal is detected or
Start signal is removed.
Fischer Panda Generator
Wiring Example:
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Default values for battery system: ____
VAh
____
64V
Ah
V
20%
Normal
10%
10%
F
96%
0.3
Off
0
1000A
0.0%
10 mA
No
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